APIs
PATCH /cms/author/groups/{group_id}/members/{author_id}/role
DELETE /cms/author/groups/{group_id}/members/{author_id} — includes leave when author_id is caller
Also includes
OWNER-only ADMIN rules; last-owner guards
Migration c3d4e5f6a7b8 — remove EDITOR, migrate to ADMIN
PR: #661
APIs
PATCH /cms/author/groups/{group_id}/members/{author_id}/role
DELETE /cms/author/groups/{group_id}/members/{author_id} — includes leave when author_id is caller
Also includes
OWNER-only ADMIN rules; last-owner guards
Migration c3d4e5f6a7b8 — remove EDITOR, migrate to ADMIN
PR: #661